This project investigates how rhesus monkeys and other nonhuman primate species born and raised under different laboratory conditions adapt to placement into naturalistic outdoor environments that contain specific physical and social features of the monkeys' natural habitat. Adaptation is assessed by examining behavioral repertoires and by monitoring a variety of physiological systems in these subjects, yielding broad-based indices of relative physical and psychological well-being. The responses of subjects to experimental manipulations of selected features of their respective environments are also assessed in similar fashion. During FY94 construction of a new addition to the shelter facility for the LCE's 5-acre outdoor enclosure at the NIHAC was begun, curtailing some of the ongoing research with the resident rhesus monkey troop. However, data collection for a series of studies investigating spacial memory capabilities regarding the location of familiar and novel objects within the 5-acre enclosure was completed, and the effects of the physical and social disruption produced by the construction on ongoing troop behavior and habitat usage was documented. Lifespan longitudinal behavioral profiles exhibited by a comparison group of rhesus monkeys maintained from birth in indoor housing demonstrated remarkable stability of both individual and gender-specific profiles from early adulthood to senescence, despite significant developmental changes in certain behaviors as a function of increasing age. Extensive studies investigating tool-using behavior in capuchin monkeys greatly expanded the known range and complexity of tool-using tasks that the species is capable of mastering, including certain tasks previously thought to be limited to humans and their direct hominid ancestors. Another set of studies employed video game technology to demonstrate impressive cognitive capabilities involving elements of self-recognition in capuchin monkeys qualitatively similar to those of chimpanzees and humans. Data from several field studies investigating the relationship between group social structure and context and acoustical features of vocalizations in 3 species of New World primates were published this past year. Finally, major methodological advances were achieved in the editing and analysis of psychophysiological data collected via telemetry from free-ranging monkeys, as well as in the development of sophisticated growth curve modelling techniques for analyzing small-n longitudinal data sets.